If there’s one thing that all musicians tend to fret over, it’s pitch. That's a little easier to hear than to try to describe, but when you’re listening to your favorite song being tortured at a local karaoke spot, you’ll know when it’s not being kept in tune by some buzzed bar patron. There are more than a couple of competent iOS apps that use the built-in microphone and/or incoming audio signal, sample it, and check to see if it is indeed in tune, but Tunable puts a truly new, innovative spin on the overall concept. In the process, it delivers on the promise of being a one-stop tuning shop.